ETS - Electric Thermal Storage Heating
Considerations for Electric In-floor Heating:
Electric Thermal Storage (ETS) is a relatively new heating concept in North America, but not a new technology. It has been used successfully in Europe for more than 40 years. The system works much like a thermos bottle, allowing the storage of heat until it is needed. A concrete slab or surface is charged during times when the local power authority is providing power at off-peak rates. When the regular rate comes into effect the thermostat goes into a setback mode and allows the charged surface to radiate heat slowly until there is a requirement for heat. The result is a savings of up to 65% off the regular heating bills, some installation have achieved an 80% off peak cycle conserving energy and saving money, with the benefits and increased of an energy efficient radiant heating home.
Electric Thermal Storage systems typically are used only where electric utilities offer "off-peak" rates. They use electricity to produce heat at off-peak times when rates are lower, and require some type of storage medium to store the heat until it is needed. Time-of-use rates allow you to "charge" the concrete floor with heat during off-peak hours (approximately 9 p.m. to 6 a.m.). If the floor's thermal mass is large enough, the heat stored in it will keep the house comfortable for 12 to 14 hours, without any further electrical input.
Link to Nova Scotia Power - Electric Thermal Storage
Construction and Operation
Thermal mass is the ability of a material to absorb, store and release heat.
At a minimum, the basement (or slab, if there is no basement) must be thermally heated. A 4” slab with a minimum of 2” of rigid insulation underneath offers best thermal retention.
Upper levels can be heated with in-floor as long as an over-pour of 2” concrete is used.
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